5 

cop  ?>o 


STATE  OF  ILLINOIS 
DEPARTMENT  OF  REGISTRATION  AND  EDUCATION 

DIVISION  OF  THE 
STATE  GEOLOGICAL  SURVEY 

M.  M.  LEIGHTON.  Chief 


Cooperative  Mining  Series 

BULLETIN  30 


GOAL  LOSSES  IN  ILLINOIS 

BY 

C.  A.  ALLEN 


ILLINOIS  MINING  INVESTIGATIONS 

Prepared  by  the  U.  S.  Bureau  of  Mines,  with  the  collaboration  of  the  Illinois 

Geological  Survey  and  the  Engineering  Experiment  Station 

of  the  University  of  Illinois 


PRINTED  BY  AUTHORITY  OF  THE  STATE  OF  ILLINOIS 


URBANA,  ILLINOIS 
1925 


The  Forty-seventh  General  Assembly  of  the  State  of  Illinois,  with 
a  view  of  conserving  the  lives  of  the  mine  workers  and  the  mineral 
resources  of  the  State,  authorized  an  investigation  of  the  coal  resources 
and  mining  practices  of  Illinois  by  the  Department  of  Mining  Engi- 
neering of  the  University  of  Illinois  and  the  State  Geological  Survey 
Division  in  cooperation  with  the  United  States  Bureau  of  Mines.  A 
cooperative  agreement  was  approved  by  the  Secretary  of  the  Interior 
and  by  representatives  of  the  State  of  Illinois. 

The  direction  of  this  investigation  is  vested  in  the  Director  of  the 
United  States  Bureau  of  Mines,  the  Chief  of  the  State  Geological 
Survey  Division,  and  the  Director,  Engineering  Experiment  Station, 
University  of  Illinois,  who  jointly  determined  the  methods  to  be 
employed  in  the  conduct  of  the  work  and  exercise  general  editorial 
supervision  over  the  publication  of  the  results,  but  each  party  to  the 
agreement  directs  the  work  of  its  agents  in  carrying  on  the  investiga- 
tion thus  mutually  agreed  on. 

The  reports  of  the  investigation  are  issued  in  the  form  of  bulle- 
tins, either  by  the  State  Geological  Survey  Division,  the  Engineering 
Experiment  Station,  University  of  Illinois,  or  the  United  States 
Bureau  of  Mines.  For  copies  of  the  bulletins  issued  by  the  State 
Geological  Survey  Division,  address  State  Geological  Survey  Division, 
Urbana,  Illinois ;  for  those  issued  by  the  Engineering  Station,  address 
Engineering  Station,  University  of  Illinois,  Urbana,  Illinois;  and  for 
those  issued  by  the  U.  S.  Bureau  of  Mines,  address  Director,  U.  S. 
Bureau  of  Mines,  Washington,  D.  C.     (See  list  at  end  of  book.) 


ILLINOIS  STATE  GEOLOGIC^  SURVEY 

HUH? 

3  3051  00006  3895 


STATE  OF  ILLINOIS 
DEPARTMENT  OF  REGISTRATION  AND  EDUCATION 

DIVISION  OF  THE 
STATE  GEOLOGICAL  SURVEY 

M.  M.  LEIGHTON,  Chief 


Cooperative   Mining   Series 

BULLETIN  30 


COAL  LOSSES  IN  ILLINOIS 


BY 
C.  A.  ALLEN 


ILLINOIS  MINING  INVESTIGATIONS 

Prepared  by  the  U.  S.  Bureau  of  Mines,  with  the  collaboration  of  the  Illinois 

Geological  Survey  and  the  Engineering  Experiment  Station 

of  the  University  of  Illinois 


IMJINTKI)    15V    A1TIIOKIIY    OF   THE    STATE    OK    ILLINOIS 


DRBANA,  ILLINOIS 
11)25 


STATE  OF  ILLINOIS 
DEPARTMENT  OF  REGISTRATION  AND  EDUCATION 

DIVISION  OF  THE 

STATE  GEOLOGICAL  SURVEY 

M.  M.  LEIGHTON,   Chief 


Committee  of  the  Board  of  Natural  Resources 
and  Conservation 

A.  M.  Sheltox.  Chairman 

Director  of  Registration  and  Education 

Kendric  C.  Babcock 

Representing   the    President   of   the    Uni- 
versity of  Illinois 

Edson  S.  Bastin 
Geologist 


Schnepp  &  Barnes,  Printers 

Springfield,  III. 

1925 

32714—2500 


PREFACE 

In  the  course  of  the  inquiry  conducted  by  the  Bureau  of  Mines,  Depart- 
ment of  the  Interior,  for  the  United  States  Coal  Commission,  into  losses  in- 
curred in  mining  bituminous  coal  in  the  eastern  part  of  the  United  States,  a 
study  was  made  of  the  principal  coal-mining  districts  of  Illinois  by  the  late 
C.  A.  Allen. 

Coal  losses  in  the  Illinois  field  have  received  unfavorable  comment  from 
mining  engineers  for  at  least  a  decade,  and  the  present  period  of  depression 
is  serving  to  awaken  the  interest  of  the  more  progressive  operators  in  the 
problem.  It  is  believed  that  the  presentation  of  the  detailed  data  obtained  by 
Mr.  Allen,  not  involving  mine  labor  and  surface  subsidence  problems,  will  be 
of  value  to  those  concerned  with  the  coal  industry. 

The  chief  merit  of  the  report  lies  in  the  fact  that  it  is  the  result  of  a 
comprehensive  and  systematic,  though  rapid,  survey  of  the  more  important 
coal  mining  districts  of  the  State  by  an  especially  competent  and  impartial 
observer. 

The  coal-mine  operators  of  Illinois  cordially  cooperated  in  supplying 
data  requested,  assisted  in  preparing  records  and  estimates,  and  courteously 
facilitated  examination  of  mines  and  records.  Advice  and  assistance  were 
also  cordially  given  Mr.  Allen  in  his  studies  by  the  various  officials  of  the 
State  mining,  geological,  and  educational  branches. 

The  work  was  conducted  through  C.  E.  Lesher  of  the  Engineering  divi- 
sion of  the  Commission,  and  his  assistant,  W.  M.  Drake,  Jr.,  and  was  under 
the  supervision  of  H.  Foster  Bain,  Director  of  the  U.  S.  Bureau  of  Mines,  and 
George  S.  Rice,  chief  mining  engineer  of  the  Bureau  of  Mines,  and  during 
his  absence  in  Europe,  of  J.  W.  Paul,  chief  of  coal-mining  investigations  of 
the  Bureau. 

M.  M.  LEIGHTON,  Chief, 
Illinois  Geological  Survey. 


CONTENTS 

PAGE 

General  summary  7 

Coal  losses  in  the  Northern  Illinois  coal  field 7 

Introduction    7 

Losses  in  overlying  coal 9 

Coal  losses  in  the  Peoria  and  Fulton  county  fields 9 

Introduction    9 

Losses  of  coal 10 

Avoidable  losses    11 

Coal  losses  in  the  Central  and  Belleville  districts 12 

Introduction    12 

Description  of  coal  seam 12 

Character  of  roof  and  floor 13 

Method  of  mining 14 

Calculation  of  coal  losses 15 

Actual  figures  on   extraction 15 

Belleville  field   15 

Central  Illinois  field 15 

Avoidable  losses   16 

Coal  losses  in  the  Springfield  district 18 

Introduction    18 

Coal  reserves   18 

Beds  being  worked 18 

Nature  of  roof  and  floor 19 

Method   of  mining 19 

Surface  value  of  land 20 

Calculation  of  losses 20 

Avoidable  losses    24 

Actual  extraction 21 

Conclusion    22 

Coal  losses  in  the  Southern  Illinois  field 23 

Introduction    23 

Character  of  roof  and  floor 23 

Method   of  mining 24 

Calculation  of  coal  losses 25 

Actual   extraction 26 

Conditions  in  Jackson  County 27 

Average  coal  losses 28 

Avoidable  loss   29 

Coal  losses  in  Saline  County 29 

Introduction    29 

Characteristics  of  the  seam 29 

Dimensions  of  working  places 29 

Losses  of  coal 30 

Avoidable  loss   30 

Loss  in  overlying  seam 31 

Coal  losses  in  the  Danville  district 31 

Introduction    31 

Method  of  mining 33 

Losses  of  coal 34 

Avoidable  loss  34 

GO 


ILLUSTRATIONS 

FIGURE  PAGE 

1.  Section  of  mine  workings  in  Greene  County,  showing  coal  lost  by 

caved  roof  due  to  thin  pillars 13 

2.  Section  of  mine  workings  in  St.  Clair  County,  showing  pillars  not 

extracted    16 

3.  Coal  lost  by  protection  of  surface  improvements.     Section  of  mine 

workings  in  Randolph  County 17 

4.  Section  of  mine  workings   in   Sangamon   County,   showing   pillars 

not  extracted   22 

5.  Section  of  mine  workings  in  Jackson  County,  showing  pillars  not 

extracted    27 

6.  Section  of  mine  workings  in   Saline  County,   showing  pillars  not 

extracted  and  coal  lost  because  of  irregular  workings  and  due  to 
displacement  faults   30 

7.  Section  of  mine  workings  in  Vermilion  County,  showing  coal  lost 

because  of  irregular  spacing  and  direction  of  rooms 33 


TABLES 

PAGE 

1.  Coal  production  of  mines  in  northern  Illinois 7 

2.  Summary  of  coal  losses  in  northern  Illinois 8 

3.  Summary  of  coal  losses  in  Peoria-Fulton  county  fields 11 

4.  Coal  production  of  the  Belleville  and  Central  fields 12 

5.  Summary  of  coal  losses  in  the  Belleville  and  Central  fields 17 

6.  Summary  of  coal  losses  in  the  Springfield  district 21 

7.  Summary  of  coal  losses  in  southern  Illinois 28 

8.  Summary  of  coal  losses  in  Saline  County 31 

9.  Summary  of  coal  losses  in  the  Danville  district 34 


(-•) 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  Illinois  Urbana-Champaign 


http://archive.org/details/coallossesinilli30alle 


GOAL  LOSSES  IN  ILLINOIS 

By  C.  A.  Allen 

GENERAL  SUMMARY 

Eleven  fields  in  twenty-seven  counties  are  discussed  in  this  report, 
and  represent  nearly  the  whole  of  the  coal  output  of  Illinois,  which 
amounts  to  between  60  and  88  million  tons  annually.  In  1921  the  out- 
put was  almost  70  million  tons.  Twenty  mines  were  examined  and 
data  were  procured  from  131  mines,  accounting  for  half  of  the  coal 
mined.  Omitting  the  Northern  Illinois  field,  in  which  the  longwall 
system  of  mining  is  employed,  and  where  the  extraction  is  95  per  cent, 
the  losses  in  the  other  fields  are  much  the  same,  and  vary  between 
43  and  53  per  cent,  and  average  4!.). 7  per  cent.  This  means  that,  in 
the  mining  of  69,785,000  tons,  as  in  1921,  an  amount  almost  equal  to 
this  total,  namely  67,045,000  tons,  was  lost.  Pillars  account  for 
most  of  this  loss,  the  average  being  39  per  cent ;  but  the  investigation 
showed  that  32  per  cent  of  this  loss  is  avoidable.  Therefore,  instead 
of  the  extraction  being  50  per  cent,  it  should  be  82  per  cent.  In  south- 
ern Illinois  there  is  a  rather  large  loss  of  roof  coal — namely,  7  per  cent; 
while  in  Peoria  and  Fulton  counties  there  is  a  heavy  loss  of  15  per 
cent  due  to  coal  being  left  under  water-bearing  strata  and  wet  and 
tender  roof. 

COAL  LOSSES   IN  THE  NORTHERN   ILLINOIS  COAT. 

FIELD 
Introduction 
This  report  covers  that  part  of  northern    Illinois  where  mining  is 
carried  on  by  the  longwall  method,  and  includes  the   following: 

Table  1. — Coal  production  of  mines  in  northern  Illinois 


County 

Mines 

Tons  in  1921 

La  Salle 

l 

2 

384,813 
556,671 
229,907 
202,926 

Bureau 

Marshall 

Grundy       

Total . .  . 

16 

1,374,317 

' 

One  trip  was  made  underground  in  this   field,  and  five  operators 
were  interviewed. 

(7) 


8 


ILLINOIS    COAL    LOSSES 


In  addition  to  the  longwall  mines  which  are  working  No.  2  bed, 
or  the  so-called  "Third  Vein",  there  is  one  room-and-pillar  mine  in 
No.  5  bed.  This  mine  produces  about  170,0$Q  tons  per  year,  and  re- 
covers approximately  50  per  cent  of  the  coal.  To  include  this  with 
the  longwall  mines  would  tend  only  to  confuse,  and  as  it  has  not  suf- 
ficient tonnage  to  be  reported  alone,  it  would  seem  better  to  neglect 
this  mine  altogether. 

In  the  longwall  mines,  the  only  effort  made  was  to  determine  if 
any  appreciable  amount  of  coal  was  left  under  buildings,  railroads,  or 
streams ;  and  after  studying  this  factor,  and  discussing  the  matter 
with  three  companies,  it  was  found  that  the  coal  left  thereunder 
amounts  to  only  a  fraction  of  one  per  cent. 

The  only  other  loss  possible  is  in  the  coal  thrown  back  with  the 
impurities.  The  seam  is  about  31/,  feet  thick,  and  there  are  occasion- 
ally sulphur  bands  through  it,  but  they  occur  with  no  regularity.  Also, 
occasionally  the  roof  coal  sticks  to  the  overlying  rock.  George  S.  Rice, 
chief  mining  engineer  for  the  Bureau  of  Mines,  Department  of  the 
Interior,  states  that  careful  figures  kept  over  a  period  of  five  years 
showed  that  95  per  cent  of  the  coal  was  recovered  at  one  mine;  and 
the  late  H.  H.  Stoek  of  the  University  of  Illinois  stated  that  at  another 
mine  the  loss  from  coal  thrown  back  with  impurities  amounted  to  7 
per  cent.  Inasmuch  as  figures  from  some  other  longwall  districts 
have  shown  a  loss  of  only  4  per  cent,  it  is  assumed  that  the  loss  in  this 
field  is  approximately  5  per  cent. 

Table  2. — 8um,?nary  of  coal  losses  in  northern  Illinois 


Reason  for  loss 


Coal  left  as  roof  and  bottom  coal 

Coal  lost  in  room,  entry,  and  panel  pillars 

Coal  lost  in  oil  or  gas-well  pillars 

Coal  lost  under  buildings,  railroads  and  boundaries 

Coal  lost  in  handling  and  preparation,  underground 
and   surface    

Coal  lost  due  to  rolls,  thin  or  dirty  areas,  or 
streams      

Total  loss,  per  cent 


Percentage  of  market- 
able coal  lost  in  area 
worked 


Avoidable 

Total 

loss 

loss 

Fraction 

of  1 

None 

None 

Fraction 

of  1 

5 

None 

ILLINOIS    COAL   LOSSES 


Losses  in  Overlying  Coal 


Inasmuch  as  the  lower  seam  being  worked  is  only  Sy2  feet  thick, 
and  is  80  feet  below  No.  5  bed,  the  writer  would  not  expect  the  No.  5 
bed  to  be  seriously  affected.  At  one  mine,  where  No.  5  is  being 
worked,  it  is  reported  that  the  roof  is  cracked  a  little,  but  otherwise 
it  gives  them  no  trouble,  and  the  recovery  of  the  coal  is  not  influenced 
by  the  work  underneath. 

COAL  LOSSES  IN  THE  PEORIA  AND  FULTON  COUNTY 

FIELDS 

Introduction 

This  district  comprises  the  counties  of  Peoria,  which  has  11  ship- 
ping mines  with  a  production  of  1,102,002  tons  in  1921;  Fulton,  with 
28  mines,  producing  1,471,137  tons;  and  Tazewell,  with  7  mines,  pro- 
ducing 691,359  tons.  The  total  production  of  the  district  in  1921  was 
3,264,498  tons.  This  district  comprises  part  of  District  IV  of  the 
Illinois  Coal  Mining  Investigations,1  and  in  University  of  Illinois 
Bulletin  1002,  the  following  description  is  given : 

"In  District  IV  the  No.  5  coal  is  mined.  The  average  thickness  of  this 
coal  is  4  feet  8  inches,  according  to  data  taken  at  240  mines  and  given  in  the 
Thirty-first  Annual  Coal  Report  of  Illinois.  The  No.  5  bed  outcrops  in 
Peoria,  Fulton,  and  Knox  counties,  but  is  found  at  greater  depths  toward  the 
east. 

"The  roof  is  of  black  sheety  shale  varying  in  thickness  from  a  few  inches 
to  35  feet,  and  containing  occasionally  "nigger-heads"  of  pyrite.  In  many 
mines  there  is,  in  places,  a  layer  of  pyrite  2  or  3  inches  thick  between  the 
coal  and  the  shale.  Where  this  layer  is  present,  the  shale  is  protected  from 
the  air  and  stays  up;  where  it  is  not  present,  the  shale  falls  badly,  and  some- 
times caves  to  a  height  of  35  feet.  A  limestone  occurs  above  the  shale  in 
most  mines,  though  in  a  few  places  a  fine  grained  micaceous  sandstone  is 
found.    In  some  cases  the  shale  is  absent,  and  the  cap-rock  becomes  the  roof. 

"A  great  many  clay  veins  extend  through  the  coal  and  the  roof  shale; 
there  are  also  small  faults,  slips,  and  rolls,  and  places  where  the  coal  has 
been  eroded  and  the  space  has  been  filled  with  drift.  It  is  difficult,  therefore, 
to  calculate  the  total  tonnage  and  to  project  any  plan  of  operation.  In  many 
places  the  coal  adheres  to  the  roof  and  separates  from  it  with  difficulty.  In 
one  mine  about  an  inch  of  coal  is  left  to  protect  the  roof  shale  from  the  air. 
In  most  mines  the  floor  consists  of  a  dark  gray  clay  which  heaves  badly 
when  wet." 

The  coal  hed  in  the  area  covered  by  this  report  is  from  1  to  5 
feet  thick,  averaging  about  1  feet  1  inches.  The  principal  impurity 
consists  of  clay  veins,  which  are  very  irregular  both  in  size  and  distri- 


1  Cady,  G.  H.,  Coal  resources  of  District  IV  (Peoria-Springfleld) :  111.  Coal 
Mining  Investigations  Bull.   26,   1921. 

2  Young,  C.  M.,  Percentage  of  extraction  of  bituminous  coal  with  special 
reference  to  Illinois  conditions:  Engineering  Experiment  Station  Hull.  100,  p. 
36,   1917. 


10  ILLINOIS    COAL    LOSSES 

bution.  Two  mines  were  examined  in  the  district,  and  data  were 
secured  from  mining  engineers  of  3  other  mines.  The  method  of  min- 
ing is  room-and-pillar,  and  the  workings  are  usually  laid  out  in  panels. 
Rooms  are  driven  30  to  35  feet  on  center,  and  are  from  22  to  30  feet 
wide.  Barrier  pillars,  30  to  35  feet  wide,  are  left  along  the  main  and 
cross  entries. 

Losses  of  Coal 

Coal  is  not  left  to  support  valuable  surface  as  in  the  Springfield 
district  of  Illinois.  Some  of  it  is  good  farming  land,  but  most  of  the 
country  is  rough  and  hilly.  The  only  place  pillars  are  left  is 
along  railroads  and  streams.  In  some  parts  of  the  field  there  are 
water-bearing  formations  lying  above  the  coal,  so  that  when  the  roof 
is  cracked  a  large  quantity  of  water  comes  into  the  mine.  Just  how 
this  water  occurs  is  not  known,  but  it  apparently  does  not  affect  much 
of  the  area  being  mined.  No  attempt  is  made  to  recover  any  pillars 
either  under  water-bearing  strata  or  elsewhere.  In  addition  to  the 
coal  left  in  the  pillars  in  the  regular  work,  considerable  areas  are  left 
where  the  roof  is  very  tender  and  wet.  Theoretically,  the  area  of  the 
bed  lost  is  from  24  to  35  per  cent,  but  the  superintendent  of  one  of 
the  mines  visited  reported  that  he  had  made  a  careful  estimate,  and 
found  that  they  were  getting  only  between  45  and  50  per  cent,  which 
would  mean  a  loss  of  between  55  and  50  per  cent.  The  chief  engineer 
of  another  company  stated  that  in  1921  he  planimetered  a  map  of  the 
workings,  and  checked  it  against  the  tonnage  hoisted,  and  found  they 
had  saved  only  about  40  per  cent  of  the  area  worked  over.  From 
figures  on  the  same  mine  for  a  number  of  years  past  the  coal  saved 
amounted  to  slightly  less  than  37  per  cent.  Of  the  GO  per  cent  lost 
in  1921,  about  10  per  cent  was  lost  in  areas  abandoned  owing  to  a 
wet  and  tender  roof.  If  these  figures  had  not  been  secured,  the  writer 
would  have  placed  the  extraction  at  well  over  50  per  cent,  but  at  the 
mine  where  they  had  carefully  estimated  between  45  and  50  per  cent 
recovery  this  was  believed  to  be  a  very  good  average  of  the  district, 
so  the  figure  47  per  cent  has  been  accepted. 

In  this  field  some  solid  coal  is  left  under  streams,  and  at  the  mines 
examined  the  coal  so  left  amounted  to  approximately  3  per  cent.  In- 
asmuch as  the  railroad  ran  along  the  stream,  the  same  coal  serves  to 
support  it.  The  depth  of  the  cover  is  not  great,  ranging  from  a  few 
feet  up  to  about  150  feet,  so  that  any  caving  of  the  roof  would  be 
readily  transmitted  to  the  surface.  The  coal  lost  in  handling  and 
preparation  is  probably  not  as  high  as  in  the  Springfield  district,  be- 
cause the  clay  veins  are  less  frequent  in  most  mines,  and  consequently 
less  coal  is  wasted  in  throwing  out  the  clay. 


ILLINOIS    COAL    LOSSES 


11 


On  the  basis  of  present  information  the  writer  would  therefore 
put  the  loss  as  follows : 


Cause  of  loss 

In  room,  entry,  and  panel  pillars 

Under  streams  and  tender  roof 

In  handling  and  preparation 


Per  cent 

35 

15 

3 


Total  loss 


53 


AVOIDABLE   LOSSES 

The  coal  lost  under  streams  and  railroads  and  that  lost  in  handling 
and  preparation  are  unavoidable.  Of  the  coal  left  as  pillars,  unquestion- 
ably some  is  necessary  on  account  of  the  water  conditions  overhead. 
However,  the  pillars  which  are  now  being  left  are  not  sufficient  to 
hold  the  roof  up  for  any  great  length  of  time.  Some  of  the  operators 
claim  that  a  sandstone  not  far  above  the  coal  will  prevent  any  surface 
cracks,  which  may  be  the  case  over  part  of  the  field,  and  of  course 
where  this  is  so,  the  condition  would  be  changed  by  a  systematic  pillar 
drawing,  because  the  sandstone  would  have  to  break.  From  the 
writer's  observations,  taking  into  consideration  the  fact  that  certain 
parts  of  the  field  have  no  trouble  with  water,  and  a  high  percentage  of 
the  coal  could  be  extracted,  it  is  believed  that  ii  would  be  reasonable  to 
assume  that  75  per  cent  could  be  saved  in  the  entire  field,  which  would 
be  28  per  cent  more  than  they  are  saving  at  the  present  time — that  is, 
the  avoidable  loss  is  28  per  cent. 

Table  3. — Summary  of  coal  losses  in  PeortOrFulton  county  fields 


Reason  for  loss 

Percentage  of  total  market- 
able coal  lost  in  area  worked 

Total  loss 

None 

35 
None 

Included  in 
above  and 
last  item 

3 

15 

Avoidable  loss 

Coal  left  as  roof  and  bottom  coal ... 

Coal  lost  in  room,  entry,  and  panel  pillars.  .  . 

Coal  lost  in  oil  or  gas-well  pillars 

Coal     lost     under     buildings,     railroads     and 
boundaries    .             

28 

Coal  lost  in  handling  and  preparation,  under- 
ground and  surface 

Coal  lost  due  to  rolls,  thin  or  dirty  areas,  and 
streams"    

Total  loss,  per  cent 

53 

28 

•  Includes   coal   left   under   wet  and   tender  roof. 


12  ILLINOIS    COAL    LOSSES 

COAL  LOSSES   IN   THE   CENTRAL  AND   BELLEVILLE 

DISTRICTS 

Introduction 

The  Central  and  Belleville  districts  have  been  combined  in  this 
report  as  all  the  general  conditions  are  similar  in  both ;  but  separate 
summaries  have  been  made  for  each  district  as  there  is  a  difference 
in  the  percentage  of  coal  extracted.  The  Belleville  field  includes  what 
is  frequently  known  as  the  Centralia  field.  Some  details  of  produc- 
tion are  given  in  the  following  table : 

Table  4. — Goal  production  of  the  Belleville  and  Central  fields 


Belleville  district 

Central  district 

County 

Mines 

Tons,  1921 

County 

Mines 

Tons,  1921 

St.  Clair 

Randolph 

Clinton 

Marion 

Perry  (part) . . . 
Madison.  . 

55 

10 

5 

3 

9 

20 

6,281,000 
1,894,000 
1,165,000 
842,000 
822,000 
4,216,000 

Macoupin 

Montgomery 

Christian 

Sangamon 

(southern 

part) 

17 

9 

11 

4 

7,516,000 

322,000 

3,216,000 

1,845,000 

Four  trips  were  made  underground  in  the  two  fields,  and  definite 
data  were  secured  on  47  mines  producing  a  total  of  14,000,000  tons 
annually. 

Description  of  Coal  Seam 

The  coal  being  mined  in  these  fields  comes  from  the  No.  6  bed  of 
the  Illinois  Geological  Survey,  and  in  general,  the  conditions  are 
similar  to  the  No.  6  bed  where  it  had  previously  been  studied  in  other 
districts.  The  thickness  of  the  seam  varies  from  4^2  to  9  feet,  and 
probably  averages  7^4  Ieet.  It  is  a  little  thicker  in  the  western  part 
of  the  Belleville  field  than  it  is  in  the  eastern  part,  and  apparently 
attains  its  greatest  average  thickness  in  Macoupin  and  Christian  coun- 
ties. The  only  persistent  impurity  in  the  bed  is  the  "blue  band",  which 
occurs  about  18  inches  from  the  floor.  The  other  impurities  contained 
are  mother  coal  and  sulphur  bands.  The  latter  occur  to  a  greater 
extent  in  the  northern  part  of  the  Central  field  than  in  the  Belleville 
field. 

The  thickness  of  cover  ranges  from  16  to  232  feet  in  St.  Clair 
County,  from  45  to  330  feet  in  Randolph  County,  from  318  to  410  feet 
in  Clinton  County,  from  600  to  714  feet  in  Marion  County,  and  from 


ILLINOIS    COAL    LOSSES 


13 


86  to  287  feet  in  Madison  County— all  in  the  Belleville  field.  In  the 
Central  Illinois  field,  the  coal  in  Macoupin  County  has  a  cover  of  268 
to  380  feet ;  in  Montgomery  County,  380  to  640  feet ;  in  Christian 
County,  360  to  735  feet;  and  in  Sangamon  County,  from  270  to  328 
feet.  These  are  the  depths  of  the  working  shafts,  and  due  to  the 
generally  flat  surface  of  the  country,  give  the  approximate  thickness 
of  cover. 

Character  of  Roof  and  Floor 

The  roof  and  floor  of  No.  6  bed  in  these  districts  are,  generally 
speaking,  the  same  as  in  southern  Illinois — that  is,  there  is  the  usual 


WMII 


1  Virgin  Coal 


L— J  Coal  thatwill  be  extracted 
in  parr  or  in  whole 


Coal  Lost 


Fig.  1.  Section  of  mine  workings  in  Greene  County 
showing  coal  lost  by  caved  roof  due  to  thin 
pillars. 

cap-rock  of  limestone,  lying  from  a  few  inches  to  30  feet  above  the 
coal,  and  between  this  limestone  and  the  top  of  the  coal  there  are 
bands  of  material  grading  from  a  soft  clay  to  a  hard  "slate".  Wher- 
ever the  limestone  lies  within  a  few  inches  of  the  coal  it  makes  a  good 
roof,  but  wherever  it  is  high  above  the  coal,  and  the  material  between 
is  soft,  there  is  a  very  bad  roof  (fig.  1).  Sometimes  in  one  mine, 
an  entry  will  have  these  extremes  of  roof  within  2,000  feet.     Gener- 


14  ILLINOIS    COAL    LOSSES 

ally  the  roof  is  better  in  the  Belleville  field,  which  means  that  over 
more  of  that  area  the  cap-rock  comes  close  to  the  coal.  Because 
Madison  County  has  a  good  roof  over  much  of  the  area  it  has 
been  included  in  the  Belleville  field.  Some  roof  coal  is  left  up  in 
the  Central  field,  on  account  of  the  greater  area  of  tender  roof  and 
the  tendency  of  the  bed  to  attain  a  thicker  average. 

The  floor  is  fire  clay,  varying  in  thickness,  with  a  harder  stratum 
of  rock  below  it. 

Method  of  Mining 

Room-and-pillar  methods  of  mining  are  used  exclusively,  with 
the  exception  of  one  longwall  mine  in  Christian  County,  which  is  in 
the  No.  2  bed,  and  has  not  been  considered.  In  the  southern  part  of 
the  Belleville  field  there  are  more  mines  using  straight  room-and- 
pillar  system  than  there  are  mines  using  the  panel  system ;  but  the  op- 
posite is  the  case  in  the  Central  district.  The  widths  of  rooms  and 
pillars  vary  considerably,  and  there  is  apparently  no  relation  between 
the  thickness  of  cover  and  the  dimensions  of  the  workings,  except 
where  the  cover  is  very  shallow.  In  the  Belleville  field  one  mine  with 
a  150-foot  cover  and  a  good  roof  has  30-foot  rooms  on  60-foot  cent- 
ers ;  the  room-necks,  crosscuts,  and  room  entries  are  all  21  feet 
wide.  At  another  mine  close  by  where  the  roof  is  bad  the  entries 
are  narrowed,  but  the  dimensions  of  the  rooms  are  not  changed,  and 
reliance  is  placed  upon  the  timber  to  hold  up  the  bad  roof.  Another 
mine  in  the  Belleville  district  has  30-foot  rooms  on  54-foot  centers, 
with  wide  entries  and  crosscuts.  The  cover  is  307  feet.  Another 
mine  with  a  cover  of  380  feet  has  40-foot  rooms  on  80-foot  centers. 
Where  the  roof  is  bad  the  entries  but  not  the  rooms  are  narrowed. 
Another  mine  with  220  feet  of  cover  has  35-foot  rooms  on  70-foot 
centers;  the  entries  are  from  14  to  21  feet  wide,  and  room-necks 
and  crosscuts  are  21  feet  wide.  Nearly  all  the  rooms  are  approxi- 
mately 250  feet  in  length.  At  one  mine  in  the  southern  part  of 
the  Central  Illinois  field,  rooms  280  feet  long  are  driven  40  feet  wide 
on  80-foot  centers.  At  several  other  mines  near  the  southern  part, 
rooms  are  30  feet  wide  on  60-foot  centers ;  the  room-necks  and  entry 
crosscuts  are  all  21  feet  wide;  also  entries  are  21  feet  wide.  The 
room  crosscuts  are  30  feet  wide.  The  cover  is  309  to  342  feet.  At  one 
mine  in  the  northern  part  of  this  district,  rooms  are  26  feet  wide  on 
45-foot  centers.  The  depth  of  cover  is  about  250  feet.  At  another 
mine  rooms  are  24  feet  wide  on  40- foot  centers,  with  room-necks  12 
feet  wide.  The  entries  are  also  narrow,  the  cover  being  352  feet. 
At  one  mine  in  the  northeastern  part  of  the  Central  field,  rooms  are 


ILLINOIS    COAL    LOSSES  15 

30  feet  wide  on  55-foot  centers ;  the  cover  is  450  feet,  but  room- 
necks  and  entries  are  narrowed  to  10  or  12  feet.  In  nearly  all  mines 
where  the  panel  system  is  used  the  barrier  pillars  are  about  70  feet 
wide,  and  the  fire  pillars  between  the  ends  of  the  rooms  are  10  to  20 
feet  wide. 

Calculation  of  Coal  Losses 

Despite  the  fact  that  the  same  formation  occurs  over  the  entire 
area,  there  is  a  great  variation  in  the  immediate  roof  conditions,  and 
considerable  time  was  spent  trying  to  determine  how  much  of  the  area 
was  affected  by  the  roof  conditions.  The  State  mine  inspectors  fur- 
nished considerable  information,  also  some  mine  superintendents  and 
surveyors  were  met  who  were  familiar  with  many  different  mines. 
A  number  of  calculations  were  made,  taking  the  actual  dimensions  of 
the  working  places  as  a  basis,  and  showing  a  loss  in  the  pillars  of 
from  37  to  45  per  cent  in  the  Belleville  field,  and  from  40  to  48  per 
cent  in  the  Central  Illinois  field.  In  the  panel  work,  the  barrier  pillars 
amount  to  from  5  to  10  per  cent  of  the  total  loss ;  and  in  the 
straight  room-and-pillar  work  they  amount  to  less  than  2  per  cent. 
In  top  coal  the  loss  is  negligible  in  the  Belleville  field,  but  in  the  Cen- 
tral field  a  number  of  mines  leave  roof  coal  in  a  certain  number  of 
the  rooms.  After  much  inquiry,  it  is  believed  that  the  figure  of  1J/2 
per  cent  represents  the  average  over  the  entire  Central  field. 

ACTUAL   FIGURES   ON    EXTRACTION 
I'.KI  LEVILLE  FIELD 

Four  coal-mining  engineers  in  this  district  report  that  their  ex- 
traction is  54  per  cent,  00  to  (>5  per  cent,  52  to  55  per  cent,  and  50 
per  cent,  respectively.  The  writer  examined  a  large  number  of  maps 
in  the  Court  House  at  Belleville,  and  found  that  the  last  mentioned 
company  leaves  a  great  deal  of  pillar  coal,  and  its  extraction  could 
not  average  50  per  cent  if  the  surveying  were  accurately  done.  How- 
ever, they  were  mostly  small  mines. 

Taking  into  account  the  relatively  high  percentage  of  unusually 
good  roof  in  the  Belleville  field,  the  writer's  estimation  is  that  extrac- 
tion is  almost  55  per  cent. 

CENTRAL  ILLINOIS   FIELD 

Some  of  the  figures  of  recovery  from  No.  0  coal  in  the  Central 
field  covering  the  southern  part  of  Sangamon  County  were  given  in  the 
report  on  the  coal  losses  in  the  Springfield  District.  The  following 
figures  were  given  by  engineers  for  different  companies:  (1)  50  per 
cent;  (2)  7  mines  in  Sangamon  County  including  mines  in  No.  5  and 


16 


ILLINOIS    COAL    LOSSES 


6  beds  average  48.12  per  cent;  six  mines  in  Christian  County  oper- 
ated by  the  same  company  average  49.94  per  cent;  (3)  in  northern 
Macoupin  County,  51  y2  and  52  per  cent,  and  in  Montgomery  County, 
43  per  cent;  (4)  at  Divernon  in  northern  Macoupin  County,  47  per 
cent,  and  at  Mt.  Olive  in  southern  Macoupin  County,  48.6  per  cent ; 
(5)  mines  near  Gillespie,  50  per  cent,  except  in  one  mine  where  top 
coal  is  left  owing  to  bad  roof,  and  where  the  extraction  is  54  per 
cent.  Taking  everything  into  consideration,  the  writer  estimates 
that  the  extraction  is  50  per  cent,  based  on  the  assumption  that  no 
attempt  is  being  made  to  recover  barrier  pillars  on  the  retreat. 


J  Coal  fhatwill  be  extracted 
in  part  or  in  whole. 


Fig.  2.    Section    of    mine    workings    in    St.    Clair 
County  showing  pillars  not  extracted. 


AVOIDABLE  LOSSES 

The  principal  reason  for  leaving  the  pillars  in  this  area  is  the  high 
value  of  the  surface  land  (fig.  2)  ;  this  excuse,  however,  is  not  ap- 
plicable over  the  entire  area.  Around  Belleville,  and  in  the  entire  Belle- 
ville field,  there  is  considerable  rolling  country  where  pulling  pillars 
would  do  practically  no  damage.  In  Madison  County,  the  country 
is  rolling  from  Collinsville  to  Edwardsville ;  from  Edwardsville  to 
Staunton  it  is  very  level,  but  from  Staunton  to  Gillespie  it  is  rough 
again.     Around  Hillsboro  it  is  rough,  and  pillars  could  well  be  ex- 


ILLINOIS    COAL   LOSSES 


17 


tracted.  It  is  of  course  impossible  to  state  all  the  conflicts  that  would 
come  up  in  an  attempt  to  draw  pillars,  but  it  seems  to  the  writer  that 
80  per  cent  extraction  should  be  secured  in  the  Belleville  district  as  a 


I  Virgin  Coal 


£2-3  Coal  that  will  be  ext  racted 
in  part  or  in  whole 


Coal  Lost 


Fig.  3.  Coal  lost  by  protection  of  surface  improve- 
ments. Section  of  mine  workings  in  Randolph 
County. 


Table  5. — Summary  of  coal  losses  in  the  Belleville  and  Central  fields 


Reason  for  loss 


Percentage  of  market- 
able  coal   lost  in 
area  worked 


Coal  left  on  roof  and  bottom 

Coal  lost  in  room,  entry,  and  panel  pillars   (fig.  3) 

Coal  lost  in  oil  or  gas-well  pillars 

Coal  lost  under  buildings,  railroads,  and  boundaries 
Coal  lost  in  handling  and  preparation,  underground 

and   surface    

Coal    lost    due    to    rolls,    thin    or    dirty    areas,    and 

streams    

Total  loss,  per  cent 


18  ILLINOIS    COAL    LOSSES 

whole.  In  the  Central  field  there  is  more  level  land,  and  as  discussed 
in  the  report  on  the  Springfield  district,  some  coal  should  be  left,  so 
its  possible  extraction  is  77  per  cent. 

There  is  one  thing  that  must  be  taken  into  consideration.  In  the 
Belleville  field  limestone  forms  the  roof  in  probably  one  third  of  the 
area.  This  makes  an  excellent  roof,  and  except  where  the  limestone 
thins  out  it  should  stand  almost  indefinitely,  which  means  that  the 
workings  could  be  re-entered  at  any  time  and  the  pillars  extracted. 
If  this  should  ever  be  done,  it  would  increase  the  extraction  in  the 
Belleville  field,  taken  as  a  whole,  by  approximately  10  per  cent. 

COAL  LOSSES  IN  THE  SPRINGFIELD  DISTRICT 
Introduction 

The  district  covered  in  this  report  includes  the  counties  of  Logan, 
Macon,  Menard,  and  Sangamon.  Logan  County  has  3  shipping  mines, 
and  produces  approximately  345,000  tons ;  Macon  County  has  3  ship- 
ping mines,  and  produces  227,000  tons ;  Menard  County — the  number 
of  mines  unknown — produces  341,000  tons ;  Sangamon  County  has 
about  29  mines,  and  produces  5,957,000  tons,  of  which  1,800,000  tons 
come  from  No.  6  bed.  Practically  all  the  other  mines  in  the  counties 
named  are  in  No.  5  bed. 

In  studying  this  district,  two  trips  were  made  underground  in 
No.  5  bed,  and  one  in  No.  6  bed,  and  eight  different  maps  were  studied. 

Coal  Reserves 

The  State  Geological  Survey  of  Illinois  has  recently  made  a  care- 
ful survey  to  determine  the  coal  resources  of  the  different  fields  in  the 
State,  and  its  resource  figures  are  therefore  based  on  practical  rather 
than  on  theoretical  considerations. 

Beds  Being  Worked 

Both  No.  5  and  6  beds,  as  defined  by  the  Illinois  Geological  Sur- 
vey, are  being  worked  in  this  district.  The  mining  conditions  are 
very  similar,  with  the  exception  of  the  conditions  brought  about  by 
the  difference  in  the  impurities  which  are  found  in  the  beds.  No. 
6  bed  is  mined  in  Sangamon  County,  south  of  Springfield,  and  is  6 
to  7  feet  thick.  It  has  a  very  persistent  band  of  dirt  near  the  bottom 
called  the  "blue  band",  about  y2  inch  thick.  There  are  also  usually  two 
or  three  dirt  bands  through  the  bed,  but  they  do  not  occur  with  the 
same  regularity  as  the  "blue  band".    This  bed  lies  from  270  to  320  feet 


ILLINOIS    COAL    LOSSES  19 

below  the  surface.  The  No.  5  coal  is  from  4i/o  to  7  feet  thick,  and 
averages  approximately  6  feet.  Its  impurities  consist  of  clay  veins 
or  ''horsebacks"  as  they  are  locally  known,  and  an  occasional  band  of 
sulphur.  The  clay  veins  are  the  most  difficult  to  overcome  in  mining 
because  they  are  sometimes  found  every  15  or  20  feet  throughout  the 
bed,  and  have  a  thickness  varying  from  a  knife-blade  up  to  several 
feet.  Again,  in  other  places,  workings  will  be  carried  for  100  or  200 
feet  without  encountering  a  single  clay  vein.  The  No.  5  coal  lies 
from  160  to  600  feet  below  the  surface,  but  throughout  most  of  the 
field  it  is  from  200  to  250  feet. 

Nature  of  Roof  and  Floor 

The  immediate  roof  over  No.  5  bed  is  either  a  black  "slate"  or  a 
gray  shale,  either  of  which  varies  greatly  in  thickness.  They  are 
usually  from  6  to  18  inches  thick,  and  are  overlain  in  places  by  a  few 
thin  strata  of  soapstone  and  sandy  shale.  Above  these  softer  strata 
there  is  nearly  everywhere  a  cap-rock  of  limestone  or  sandstone  varying 
from  a  few  inches  to  several  feet  thick.  The  condition  of  the  roof  de- 
pends upon  the  toughness  of  the  immediate  roof.  As  a  rule,  the  black 
"slate"  holds  well  unless  broken  by  too  many  clay  veins  but  the  gray 
shale  is  usually  tender.  It  might  be  said  that  25  per  cent  of  the  roof  is 
very  good,  25  per  cent  is  very  bad,  and  the  remainder  medium. 

The  roof  over  No.  6  bed  is  generally  the  same  as  over  No.  5, 
and  further  study  will  be  made  regarding  it  in  the  field  farther  south. 
No  roof  coal  is  left  up  in  No.  5  bed,  but  occasionally  some  is  left  in 
No.  6  bed,  especially  in  the  entries. 

Method  of  Mining 

All  the  mines  are  opened  by  shafts,  and  the  room-and-pillar  method 
of  mining  is  employed  exclusively.  Practically  all  the  operators  are 
adopting  the  panel  method  with  10  to  50  rooms  in  each  panel.  Barrier 
pillars  of  50  to  75  feet  are  left  along  the  cross  entries,  which  are  usual- 
ly 12  feet  wide  on  42-foot  centers.  Room  entries  are  12  feet  wide 
on  32-foot  centers,  and  the  rooms  are  driven  24  to  26  feet  wide  on 
40  to  45-foot  centers.  Sometimes  the  rooms  are  holed  through  into 
the  adjoining  panel,  but  the  tendency  is  to  leave  about  a  10-foot  fire 
pillar.  No  attempt  is  made  to  recover  any  room  pillars,  and  probably 
a  very  small  percentage  of  the  barrier  pillars  will  be  recovered  on  the 
final  retreat 


20  illinois  coal  losses 

Surface  Value  of  Land 

The  reason  given  by  the  operators  for  not  pulling  any  pillars  is 
that  they  do  not  own  the  surface  rights,  and  that  the  owner  will  de- 
mand a  large  compensation  if  any  subsidence  takes  place.  It  not  in- 
frequently happens  that  a  squeeze  comes  on  which  causes  a  surface 
depression  and  forms  a  pond.  The  land  is  valued  at  from  $200  to 
$400  an  acre  for  agricultural  purposes.  In  addition,  it  has  a  senti- 
mental value  in  many  cases,  from  the  fact  that  it  has  been  owned  by 
the  same  family  for  several  generations.  So  far  as  time  permitted, 
the  writer  carefully  observed  the  topography  of  the  surface,  and  it 
can  be  stated  that  a  perfectly  level  piece  of  land  a  mile  square  is  rare. 
Usually  at  intervals  of  less  than  a  mile  there  are  areas  in  which  the 
surface  has  been  cut  by  shallow  washes.  Practically  all  the  level  por- 
tions are  tiled  at  costs  ranging  from  $10  to  $35  per  acre. 

Owing  to  the  fact  that  sufficient  coal  is  left  to  hold  up  the  sur- 
face, no  attempt  is  made  to  leave  solid  pillars  under  railroads,  build- 
ings, or  streams.  Occasionally  a  farmer  will  have  the  coal  reserved 
under  his  own  buildings,  and  one  or  two  cases  were  found  where 
pillars  had  been  left  under  power-plants.  Also,  where  a  railroad  had 
purchased  its  right-of-way  prior  to  acquisition  of  the  coal  by  the  coal 
company,  that  part  of  the  bed  which  lies  immediately  under  their 
right-of-way  may  not  be  mined. 

These  conditions  are  mentioned  because  they  must  be  taken  intu 
account  in  deciding  whether  the  coal  loss  is  avoidable  or  unavoidable. 
Undoubtedly,  under  most  tracts  the  coal  could  be  taken  out  clean, 
and  the  surface  let  down  practically  as  smooth  as  it  was  before,  and 
the  land  would  not  be  damaged  to  any  appreciable  extent  for  agri- 
cultural purposes.  The  pillar  pulling,  however,  would  have  to  be 
started  with  due  consideration  for  the  surface  topography  so  that  the 
subsidence  would  not  create  a  large  pond ;  also,  the  coal  would  have 
to  be  taken  very  clean.  If  this  were  done,  pillars  would  have  to  be 
left  under  the  railroads  and  under  the  towns — at  least,  under  all  large 
buildings.  Whether  pillars  would  be  necessary  under  the  concrete 
roads  is  a  debatable  question. 

Calculation  of  Losses 

The  coal  left  as  roof  coal  in  a  few  of  the  mines  and  distributed 
over  the  entire  field  amounts  to  only  a  fraction  of  1  per  cent,  and 
can  be  neglected.  The  coal  lost  in  the  room,  entry,  and  panel  pillars 
depends  a  great  deal  upon  the  occurrence  of  the  clay  veins.  At  one 
mine  in  No.  5  bed  where  24-foot  rooms  were  used  on  40-foot  centers, 


ILLINOIS    COAL    LOSSES 


21 


it  was  found  that  where  it  was  free  from  clay  veins,  rooms  would  be 
wider  than  24  feet,  but  where  the  clay  veins  were  frequent,  the  rooms 
would  be  sometimes  narrowed  down  to  12  feet.  One  operating  com- 
pany has  six  mines  all  developed  with  the  same  dimensions  of  work- 
ing places,  and  their  theoretical  loss  in  pillars  is  44  per  cent,  making 
a  recovery  of  56  per  cent,  not  including  the  loss  in  handling.  The 
result  of  calculations  at  another  mine  where  somewhat  larger  barrier 
pillars  are  left  indicates  a  loss  of  48  per  cent  in  pillars. 

The  coal  loss  resulting  from  handling  and  preparation  is  fairly 
high,  due  to  the  dirt  seams  in  No.  6  bed  and  the  clay  veins  in  No.  5 
bed.  The  writer  believes  that  if  the  entire  seam  were  mined,  at  least 
8  per  cent  of  the  coal  would  be  lost  owing  to  impurities ;  but  as  only 
half  of  the  seam  is  being  mined,  it  would  mean  only  a  4  per  cent  loss 
on  the  total  tonnage.     The  summary  of  the  losses  is  given  in  Table  6. 

AVOIDABLE   LOSSES 

Not  over  50  per  cent  of  the  coal  can  be  safely  mined  under  the 
towns,  and  it  would  probably  be  advisable  not  to  mine  over  40  per  cent. 
The  towns  probably  do  not  occupy  5  per  cent  of  the  total  area  being 
mined,  and  if  60  per  cent  of  the  coal  is  lost  under  them,  it  would  mean 
a  loss  of  3  per  cent.  Solid  pillars  of  coal  should  be  left  under  rail- 
roads and  under  hard-surfaced  roads.  If  it  is  assumed  that  two  rail- 
roads and  a  cement  road  cross  each  coal  holding  at  an  angle,  and  also 
that  the  coal  holdings  are  four  miles  wide,  solid  coal  800  feet  or  more 

Table  6. — Summary  of  coal  losses  in  the  Springfield  district 


Reason  for  loss 


Percentage  of  total 

marketable  coal  lost  in 

area  worked 


Coal  left  as  roof  and  bottom  coal 

Coal  lost  in  room,  entry  and  panel  pillars   (fig.  4) 

Coal  lost  in  oil  or  gas-well  pillars 

Coal  lost  under  buildings,  railroads,  and  boundaries 

Coal  lost  in  handling  and  preparation,  underground 
and   surface    

Coal  lost  due  to  rolls,  thin  or  dirty  areas,  and 
streams    

Total  loss,  per  cent 


Total 

Avoidable 

loss 

loss 

Fraction 

of  1 

44 

26 

None 

Included 

in  above 

4 

3 

51 

26 

22 


ILLINOIS    COAL    LOSSES 


wide  would  be  left.  One  thousand  feet  would  be  5  per  cent  of  four 
miles.  Even  if  from  a  conservation  standpoint  the  coal  should  be 
mined  clean  under  agricultural  land,  there  will  undoubtedly  be  some 
places  where  this  could  not  be  done.  For  instance,  where  pillars  are 
left  under  railroads  and  hard-surfaced  roads,  there  might  be  left  a 
three-cornered  piece  inside  them  which  should  be  supported.  Assum- 
ing that  pillars  could  not  be  pulled  under  20  per  cent  of  the  minable 


ffianur 
■in 


rirHDntn 


&^  Coal  that  will  be  extracted  ^■Coal  Lost 

in  part  or  in  whole 

Fig.  4.    Section  of  mine  workings  in  Sangamon  County- 
showing  pillars  not  extracted. 

area,  and  assuming  that  the  loss  in  preparation  would  be  7  per  cent, 
there  would  still  be  possible  an  extraction  of  75  per  cent,  which  would 
be  26  per  cent  more  than  is  at  present  being  saved. 

ACTUAL    EXTRACTION 

One  company's  general  manager  considers  it  questionable  whether 
the  district  is  getting  50  per  cent  of  the  coal.  This  operator  has  six 
mines  in  both  seams. 

Another  company  states  that  at  two  of  its  mines  in  No.  6  bed 
they  get  50.5  per  cent  and  55  per  cent,  respectively,  and  at  one  mine 
in  No.  5  bed  they  get  53.3  per  cent. 


ILLINOIS    COAL    LOSSES  23 

At  seven  mines  of  another  company  in  Sangamon  County  they 
get  an  average  extraction  of  48.12  per  cent. 

Conclusion 

This  district  has  been  reported  upon  separately  because  the  ques- 
tion of  surface  subsidence  injuring  very  valuable  agricultural  land  is 
the  condition  determining  the  method  of  mining.  It  is  realized  that 
from  a  practical  standpoint  it  would  be  exceedingly  difficult  to  get  the 
farmer  to  permit  all  the  coal  to  be  taken  out  from  under  his  land,  but 
on  the  other  hand,  if  an  average  of  5,000  tons  of  coal  is  left  by  the 
operator  which  he  could  mine  by  paying  for  the  land  at  a  cost  of  $300 
per  acre,  it  would  be  only  6  cents  a  ton  for  the  coal  that  is  lost,  or  3 
cents  on  his  total  tonnage.  His  saving  in  cost  of  operation  would 
be  several  times  this,  and  he  would  still  have,  in  most  cases,  good  land 
left. 

COAL  LOSSES  IN  THE  SOUTHERN  ILLINOIS  FIELD,  IN- 
CLUDING DUQUOIN  AND  MURPHYSBORO  FIELDS 

Introduction 

These  fields  include  the  counties  of  Williamson,  with  50  shipping 
mines  producing  10,784,752  tons ;  Franklin,  with  20  mines  and  12,- 
723,000  tons;  Jackson,  with  8  mines  and  1,1(54, 154  tons;  the  east- 
ern part  of  Perry  County  with  11  mines  and  1,740,000  tons,  and 
the  southeastern  part  of  Washington  County,  with  one  mine  produc- 
ing 25,300  tons.  This  tonnage  is  taken  from  the  report  of  the  Illinois 
Department  of  Mines  and  Minerals  for  the  year  ended  June  30,  1921. 
Four  trips  were  made  underground  in  this  field,  and  specific  data 
were  obtained  on  a  total  of  31  mines  producing  L3,500,000  tons.  Gen- 
eral data  were  also  secured  on  a  number  of  other  mines. 

The  coal  being  mined  in  this  district  comes  from  No.  6  bed  of 
the  Illinois  Geological  Survey,  with  the  exception  of  440,000  tons  in 
Jackson  County,  which  comes  from  No.  2  bed,  as  will  be  more  fully 
discussed  later  in  this  report.  No.  G  bed  varies  from  4  to  14  feet 
in  thickness,  and  averages  9  feet.  It  is  a  good  grade  of  coal,  and  the 
only  persistent  impurity  is  the  so-called  "blue  band",  which  varies  from 
a  fraction  of  an  inch  up  to  2  inches,  and  occurs  at  approximately  18 
inches  from  the  floor.  The  other  bands  of  impurities  are  not  regu- 
lar, and  consist  of  thin  partings  of  sulphur  or  mother  coal.  The  bed 
lies  nearly  level,  with  the  exception  of  the  western  part  along  the 
Duquoin  anticline,  where  it  frequently  dips  (5  per  cent  or  more.  Also 
along  the  Duquoin  anticline  there  is  some  faulting  with  displacements 


24  ILLINOIS    COAL    LOSSES 

sometimes  as  high  as  35  feet ;  and  in  Williamson  and  Franklin  coun- 
ties there  is  a  little  faulting  with  displacements  of  a  few  inches  to  a 
few  feet. 

Character  of  Roof  and  Floor 

In  most  places  in  this  area  the  immediate  roof  over  the  coal  is 
shale  or  "slate",  and  varies  in  strength  from  very  weak  to  firm,  but 
as  a  rule  is  considered  as  a  weak  roof.  In  some  places  the  shale 
grades  into  so-called  soapstone,  which  is  unusually  difficult  to  hold 
up  with  timbers.  In  Williamson  County  and  southern  Franklin  County 
the  shale  usually  contains  more  sand,  so  that  the  roof  is  generally 
a  little  stronger  than  in  the  rest  of  Franklin  County.  Above  the  im- 
mediate roof  there  is  the  so-called  "cap-rock",  or  limestone,  which  is 
a  hard  stratum  of  rock  varying  considerably  in  thickness.  This 
cap- rock  in  some  places  lies  close  to  the  top  of  the  coal  bed,  and  at  other 
places  it  is  25  feet  above  the  coal,  and  in  a  few  places  it  is  thought 
to  be  absent  altogether.  Where  the  cap-rock  directly  overlies  the 
coal  it  makes  an  excellent  roof,  but  the  known  area  of  such  occur- 
rences is  so  small  that  it  is  negligible.  Owing  to  the  fact  that  roof 
coal  is  left  up  over  a  large  part  of  the  workings,  the  exact  nature  of  the 
roof  is  not  so  well  known  as  would  be  the  case  otherwise. 

The  floor  below  No.  6  bed  is  of  fire  clay  from  a  few  inches  to 
many  feet  thick,  probably  averaging  4  to  6  feet.  Below  the  fire  clay 
there  is  usually  a  harder  rock   stratum. 

The  cover  varies  from  a  few  feet  near  the  outcrop  in  William- 
son County,  to  over  600  feet  towards  the  north  end  of  the  field ;  and 
it  probably  averages  300  feet. 

Method  of  Mining 

Most  of  the  coal  comes  from  mines  using  the  room-and-pillar, 
panel  system,  but  there  are  a  large  number  of  mines,  especially  in 
Williamson  County,  which  use  the  straight  room-and-pillar  system. 
Two  mines  in  this  county  were  found  to  have  the  rooms  20  feet  wide 
with  40-foot  centers,  with  rooms  250  to  300  feet  long.  The  entries 
were  12  feet  wide  on  37-foot  centers.  Another  mine  has  rooms  21 
feet  wide  on  40- foot  centers,  with  entries  12  feet  wide  on  30-foot 
centers.  Another  mine  has  rooms  23  feet  wide  on  36-foot  centers.  In 
Franklin  County,  where  the  cover  is  greater,  one  mine  250  feet  deep 
employs  the  panel  system,  with  rooms  24  feet  wide  on  40-foot  centers. 
Another  mine  450  feet  deep  has  24-foot  rooms  on  45-foot  centers, 
and  the  rooms  are  250  feet  long.  This  mine  is  operated  on  the  panel 
system,  and  it  has  been   found  that  the  rooms  can  all   be  completed 


ILLINOIS    COAL   LOSSES  25 

and  the  inside  ends  of  many  pillars  extracted  before  a  squeeze  occurs. 
An  adjoining  mine  uses  24-foot  rooms  on  40-foot  centers,  and  seldom 
is  able  to  get  rooms  driven  up  before  a  squeeze  takes  place. 

The  panel  system  of  mining,  which  is  in  most  general  use,  con- 
sists of  driving  the  panel  centers  towards  each  other,  and  leaving  a 
20-foot  pillar  between  them.  There  are  30  rooms — that  is,  15  on  each 
side  of  each  panel  entry — which  would  make  60  rooms  to  the  double 
panel.  Barriers  or  side  pillars  along  the  cross  entries  are  100  feet 
or  110  feet.  At  several  mines  pillar  pulling  has  been  done,  but  usually 
only  to  a  very  small  extent,  because  as  a  rule  the  pillars  are  too  thin 
to  be  extracted. 

Calculation  of  Coal  Losses 

Figures  for  a  typical  mine  in  Franklin  County,  when  calculated 
according  to  the  actual  dimensions  of  the  working  places,  gives  a  loss 
of  45^  per  cent  in  the  pillars,  of  which  about  12  per  cent  is  in  the 
barrier  pillars,  and  a  little  over  20  per  cent  in  room  pillars  and  room 
stumps.  No  attempt  is  made  to  save  any  of  these  pillars  except  the 
inside  ends,  which  have  been  considered  as  saved  in  this  calculation. 
The  roof  coal  is  all  left  up  at  this  mine,  and  it  amounts  to  14  per  cent 
of  the  thickness  of  the  bed,  or  about  8  per  cent  of  the  total  coal.  To 
this  there  should  be  added  about  3  per  cent  for  loss  in  handling 
and  preparation,  giving  a  total  loss  of  56^  per  cent. 

At  a  mine  in  Williamson  County,  where  straight  room-and-pillar 
mining  is  employed,  the  actual  dimensions  indicate  a  loss  of  40  per 
cent  in  pillars ;  but  only  about  a  third  of  the  top  coal  is  lost,  the  re- 
mainder being  taken  down  after  the  rooms  are  completed.  At  this 
mine  the  loss  in  top  coal  is  only  3  per  cent,  and  if  3  per  cent  is  added 
for  loss  in  handling,  the  total  loss  will  be  46  per  cent. 

At  one  mine  in  Jackson  County,  which  employs  the  straight  panel 
system  with  20  rooms  to  a  panel,  the  rooms  being  22  feet  wide  and 
the  pillars  23  feet  wide,  the  loss  in  pillars  figures  57  per  cent,  and 
the  loss  in  top  coal,  10  per  cent,  which  gives  a  total  loss  of  70  per 
cent,  including  3  per  cent  for  loss  in  handling. 

The  loss  of  coal  due  to  faults  is  nothing  in  the  majority  of  the 
mines,  but  may  be  5  per  cent  in  others,  although  it  probably  does 
not  average  more  than  1  per  cent  over  the  entire  field.  There  are 
also  very  few  reservations  except  near  the  outcrop,  where  the  cover 
is  shallow,  though  occasionally  in  other  parts  of  the  field,  reserva- 
tions are  left  under  certain  farmhouses  or  cemeteries,  but  as  near 
as  the  writer  could  determine,  these  would  not  average  over  0.5  per 
cent. 


26  illinois  coal  losses 

Actual  Extraction 

Fortunately  there  are  a  number  of  actual  calculations  available, 
made  by  different  engineers,  which  furnish  good  data  on  the  recov- 
ery in  this  field.  For  instance:  (1)  the  average  of  three  mines  in 
Williamson  County  is  56.59  per  cent;  (2)  the  actual  extraction  of 
another  company  from  two  mines  in  the  same  county  is  61  per  cent; 
(3)  careful  planimeter  measurements  made  of  three  mine  maps  gave 
an  average  extraction  of  45.4  per  cent,  of  which  5^  per  cent  was 
due  to  top  coal  and  2^  per  cent  to  coal  left  under  ponds  and  as 
boundary  pillars;  and  (4)  three  mines  in  this  county  gave  50  per 
cent.  Giving  each  mine  the  same  weight,  the  average  extraction  for 
the  11  mines  is  52J/>  per  cent.  In  Franklin  County,  two  mines 
of  one  company  give  an  average  recovery  of  49^2  per  cent.  The 
writer  was  also  able  to  secure  other  information  regarding  three 
mines,  one  of  which  had  an  extraction  of  42.7  per  cent;  another,  39^4 
per  cent;  and  another,  31.9  per  cent.  There  are  also  some  reliable 
data  given  in  Bulletin  100::  of  the  University  of  Illinois.  This  was  the 
work  in  charge  of  the  late  H.  H.  Stoek,  who  had  four  engineers  care- 
fully taking  measurements  under  his  direction.  On  account  of  the  care 
with  which  this  work  was  done,  the  following  has  been  abstracted  from 
the  publication  mentioned : 

"The  coal  mined  is  the  No.  6  bed  of  the  State  Geological  Survey  classifi- 
cation. Measurement  of  113  sections  taken  in  twelve  of  the  largest  mines 
in  the  county  gave  an  average  thickness  of  9.2  feet  of  coal,  the  average  min- 
imum thickness  for  the  same  twelve  mines  being  8  feet,  and  the  average  max- 
imum thickness  10.64  feet.  The  blue  band,  which  is  characteristic  of  No.  6 
bed,  varied  from  %  to  2  inches  in  thickness,  and  its  average  distance  from 
the  floor  was  21.5  inches.  Owing  to  the  difficulty  of  keeping  up  the  shaly 
material  above  the  coal  bed,  the  top  coal  is  almost  generally  left  as  roof  pro- 
tection, and  up  to  the  present  time,  very  little  of  this  top  coal  has  been  re- 
covered, although  some  operators  are  expecting  to  recover  it  at  a  later  date 
in  connection  with  pillar  drawing.  In  one  of  the  twelve  mines  from  which 
the  data  were  obtained,  top  coal  was  not  left  in  the  rooms.  This,  however, 
is  exceptional  practice,  the  average  thickness  of  the  top  coal  left  in  the 
twelve  mines  being  iy2  feet.  The  average  thickness  of  coal  mined  was  7.46 
feet,  and  the  average  tonnage  per  acre  to  January  1,  1916,  was  6,627  tons. 
This  is  equivalent  to  40.7  per  cent  extraction,  if  it  is  assumed  that  all  the  9.2- 
foot  bed  is  available  for  shipment,  or  to  41.6  per  cent  if  it  is  assumed  that 
the  blue  band  and  refuse  discarded  in  the  loading,  or  0.2  foot,  is  deducted 
from  the  thickness  of  the  bed.  A  very  careful  estimate  for  each  of  the  twelve 
mines  noted,  made  by  dividing  the  total  amount  of  coal  in  the  area  mined  up 
to  January  1,  1916,  into  the  actual  shipments  since  the  mine  began  operating, 


3  Young,  C.  M.,  Percentage  of  extraction  of  bituminous  coal  with  special 
reference  to  Illinois  conditions:  Engineering  Experiment  Station  Bull.  100,  p. 
46,   1917. 


ILLINOIS    COAL   LOSSES 


2? 


gave  percentages  of  extraction  varying  from  37.7  to  49.5,  or  an  average  of 
41.4  per  cent." 

Conditions  in  Jackson  County,  Including  No.  2  Bed 

In  Jackson  County,  1,640,154  tons  of  coal  was  produced  in  1921, 
of  which  approximately  440,000  tons  came  from  four  mines  working 
No.  2  bed,  these  mines  being  situated  in  what  is  known  as  the  Mur- 
physboro  district.     The  remainder  of  the  production  came  from  No. 


r 


*M 


HHffi'f 

mi  M  i 

|IM|I|    i 

HiiSiih 


!lfel|l|M 


MlJlflU 
lllhll>l 


i 
jJSliHIiLJl 

i 
i 


I! 

il 

■  ■ 

n 


a 


_J 


Virgin  Coal 


ESSCoal  that  will  be  extracted 
m  part  or  m  whole 


Coal  lost 


Pll 


5.    Section  of  mine  workings  in  Jackson  County 
showing  pillars  not  extracted. 


6  bed.  No.  2  bed  is  from  5  to  7  feet  in  thickness,  and  about  half  of 
the  tonnage  came  from  where  the  entire  bed  was  being  worked,  but 
some  top  coal  was  left  in  the  entries.  The  remainder  of  the  tonnage 
came  from  a  lower  bench  only  of  No.  2  bed,  because  the  bed  splits 
into  two  benches,  the  bottom  of  which  is  2>y2  to  4  feet  thick  and  the 
top  bench  2  feet  thick.    The  band  between  the  two  benches  varies  from 


28 


ILLINOIS    COAL   LOSSES 


6  inches  to  26  feet.  This  means  that  where  the  lower  bench  only  is 
worked,  the  top  bench  is  lost,  but  of  course  it  could  not  be  saved  where 
the  parting  is  very  thick.  No  mines  were  visited  in  this  field,  but 
this  information  is  gathered  from  a  bulletin  of  the  Illinois  Coal 
Mining  Investigations,4  by  S.  O.  Andros,  and  from  Frank  Rossbottom, 
the  State  mine  inspector  in  this  district.  It  can  be  readily  seen  that 
because  some  top  coal  is  lost,  and  there  is  very  small  tonnage,  tc 
include  the  No.  2  bed  in  this  report  cannot  appreciably  affect  the  re- 
sults. One  company  states  that  it  gets  an  extraction  of  50  per  cent 
from  its  mines  in  No.  2  bed  in  Jackson  County. 

Average  Coal  Losses 

In  Franklin  County  the  recovery  figures  are  all  around  41  or  42 
per  cent,  with  the  exception  of  one  company ;  and  owing  to  the  fact 
that  the  mines  in  this  county  are  not  very  old,  and  the  low  figures 
given  were  very  carefully  taken,  they  are  probably  correct.  In  Wil- 
liamson County  most  of  the  figures  are  over  50  per  cent,  but  at  the 
small  mines  the  extraction  is  almost  as  low  as  in  Franklin  County,  and 
there  are  many  small  mines.  Squeezes  are  also  common  in  all  of  the 
counties.  Taking  everything  into  consideration,  the  average  recovery 
for  the  area  is  about  47  per  cent,  including  about  one-fourth  of 
the  barrier-pillar  coal  on  the  retreat,  which  may  be  saved. 


Table  7. — Summary  of  coal  losses  in  southern  Illinois 


Reason  for  loss 


Coal  left  as  roof  and  bottom  coal 

Coal  lost  in  room,  entry,  and  panel  pillars   (fig.  5) 

Coal  lost  in  oil  or  gas  well  pillars 

Coal  lost  under  buildings,  railroads,  and  boundaries 

Coal  lost  in  handling  and  preparation,  underground 

and   surface    


Percentage  of  total 

marketable  coal  lost  in 

area  worked 


Coal    lost    due    to    rolls,    thin    or    dirty    areas, 
streams    

Total  loss,   per   cent 


and 


4  Andros,   S.   O.,   Coal   mining:  practice  in   District  II :   111.   Coal  Mining  Investi- 
gations Bull.   7.  1914. 


ILLINOIS    COAL    LOSSES  29 

AVOIDABLE    LOSS 

The  land  in  this  district  has  little  surface  value,  except  where 
close  to  a  growing  town.  Some  of  it  is  absolutely  worthless,  and  very 
little  of  it  is  worth  more  than  $50  an  acre.  There  is  little  reason  to 
suppose  that  pillars  could  not  be  pulled  in  this  field  and  at  least  83 
per  cent  of  the  coal  saved.  This  estimate  does  not  involve  removal  of 
the  top  coal. 

COAL  LOSSES  IN  SALINE  COUNTY 
Introduction 

This  report  covers  the  mining  of  No.  5  coal  bed  in  Saline  County. 
There  were  23  shipping  mines  listed  in  the  report  of  the  State  Depart- 
ment of  Mines  and  Minerals  for  the  fiscal  year  ending  June  30,  1921, 
their  total  production  being  4,245,132  tons. 

One  trip  was  made  underground,  and  figures  were  obtained  from 
operators  representing  the  production  of  nearly  2,000,000  tons.  The 
bed  ranges  in  thickness  from  I  to  T  feet,  averaging  a  little  less  than 
6  feet.  All  mining  is  done  by  room-and-pillar  methods,  and  in  most 
mines  the  panel  system  is  employed.  Most  of  the  mines  are  opened 
by  shafts,  varying  in  depth  from  65  to  505  feet,  with  an  average  of 
probably  235  feet. 

Characteristics  of  the  Seam 

From  observations  in  the  mine  visited,  and  from  data  secured 
from  other  operators,  it  is  evident  that  the  roof  conditions  over  this 
coal  bed  are,  as  a  rule,  excellent.  The  roof  is  gray,  sandy  shale,  and 
stands  up  remarkably  well.  The  seam  is  clean,  comparatively  speak- 
ing. Occasionally  a  thin  streak  of  "draw-slate"  comes  in  between  the 
coal  and  the  good  top.  The  floor  is  of  fire  claw  which  in  places  con- 
tains sand,  and  like  most  of  the  floor  in  the  Illinois  mines,  heaves 
when  wet.  The  floor  is  also  very  rolling,  frequently  making  it  neces- 
sary to  have  steep  grades  on  the  entries,  or  else  run  them  around  the 
high  spots. 

Dimensions  ok  Working  Places 

Some  operators  drive  wide  entries  of  18  feet  or  more,  leaving 
about  30  feet  of  pillar  between,  and  others  drive  entries  only  12  feet 
wide.  Rooms  are  from  24  to  28  feet  wide,  and  pillars  are  12  to  18 
feet  thick.  Sometimes  room-necks  are  narrow,  but  more  frequently 
the  rooms  are  started  about  20  feet  wide,  and  gradually  widened  to 
their  full  width.     Room  crosscuts  are  18  to  20  feet  wide, 


30 


ILLINOIS    COAL    LOSSES 


Losses  of  Coal 

From  calculations  made  at  the  mine  visited,  which  was  said  to  be 
an  average  of  the  district,  the  loss  in  pillars,  including  75-foot  barrier 
pillars,  amounts  to  38  per  cent.  Owing  to  the  cleanliness  of  the 
seam,  the  coal  thrown  back  into  the  gob  does  not  amount  to  over  3 
per  cent.  Unfortunately  the  beds  are  cut  by  numerous  faults,  with 
throws  of  from  a  few  inches  to  over  100  feet.  It  is  difficult  to  ar- 
range the  plan  of  a  mine  to  get  all  the  coal  along  these  faults,  and  also 
the  roof  is  bad  near  them.     One  operator  claimed  that  they  had  lost 


I  Virgin  Coal      IM1  Coal  that  will  be  extracted 
in  part  or  in  whole. 


Coal  Lost 


Fig.  6.  Section  of  mine  workings  in  Saline  County 
showing  pillars  not  extracted  and  coal  lost  be- 
cause of  irregular  workings  and  due  to  displace- 
ment faults. 

no  coal  on  account  of  faults  as  yet,  whereas  the  map  of  another  mine 
showed  a  loss  of  about  10  per  cent.  Probably  5  per  cent  represents 
an  average  loss. 

Actual  figures  of  extraction,  as  reported  to  the  writer,  were  as 
follows:  (1)  57.06  per  cent;  (2)  3  mines,  51  per  cent,  51.5  per  cent, 
and  53.3  per  cent;  (3)  51  per  cent. 

AVOIDABLE  LOSS 

The  conditions  in  this  field,  as  far  as  the  coal  bed  is  concerned, 
are  ideal   for  pillar  pulling.     From  the  standpoint  of   surface  condi- 


ILLINOIS    COAL    LOSSES 


31 


tions,  the  land  is  valuable  for  farming,  but  not  so  valuable  as  that  in 
the  Springfield  district.  Also  it  is  more  broken,  and  very  little,  if 
any,  is  tilled.  There  are  fewer  towns  and  fewer  railroads.  The  land 
is  occasionally  flooded  by  high  water  in  Ohio  and  Wabash  rivers,  but 
the  mining  companies  could  well  afford  to  build  levees  as  high  as  the 
ground  would  subside  from  pillar  drawing,  if  such  would  be  neces- 
sary. Taking  everything  into  consideration,  an  extraction  of  85  per 
cent  ought  to  be  secured  in  this  field. 

LOSS   IN   OVERLYING  SEAMS 

The  No.  6  bed  is  about  70  feet  above  No.  5  in  this  area,  and  is  of 
workable  thickness.  As  mining  is  now  carried  on,  No.  6  seam  will 
not  be  affected  except  where  squeezes  occur,  or  where  caves  in  rooms 
extend  up  to  it,  which  is  rare.  On  the  whole,  it  is  the  writer's  opinion 
that  very  little  coal  in  No.  6  bed  is  at  present  being  lost,  but  informa- 
tion either  for  or  against  this  conclusion  could  not  be  obtained. 


Table  8. — Summary  of  coal  losses  in  Saline  County 


Reason  for  loss 


Coal  left  as  roof  and  bottom  coal 

Coal  lost  in  room,  entry,  and  panel  pillars 

Coal  lost  in  oil  or  gas-well  pillars 

Coal  lost  under  buildings,  railroads,  and  boundaries 

Coal  lost  in  handling  and  preparation,  underground 
and   surface    

Coal  lost  due  to  rolls,  thin  or  dirty  areas,  and 
streams"    (fig.   6 ) 


Percentage  of  total 

marketable  coal  lost  in 

area  worked 


Total 

Avoidable 

loss 

loss 

None 

38 

31 

None 

Included 

in  above 

3 

5 

•• 

46 

31 

Total  loss,  per  cent 

a  Includes  coal  along  faults. 

COAL  LOSSES  IN  THE  DANVILLE  DISTRICT 

Introduction 

The  Danville  district  has  7  mines  in  No.  6  bed  and  5  mines  in 
No.  7  bed,  but  by  far  the  largest  production  comes  from  the  former. 
It  includes  Vermilion  County  only,  and  has  a  total  production  of  slight- 


32  ILLINOIS    COAL    LOSSES 

ly  over  3,000,000  tons,  of  which  about  450,000  tons  come  from  strip 
or  open-cut  mines. 

No  trips  were  made  underground  while  studying  this  field,  but 
operators  were  interviewed  who  mine  over  half  of  the  total  tonnage. 

The  characteristics  of  the  beds  have  been  described  by  S.  O. 
Andros  in  a  bulletin  of  the  Illinois  Mining  Investigations  series,5  as 
follows : 

"In  this  district  all  the  large  outputs  are  produced  from  the  No.  6  bed  of 
the  Illinois  State  Geological  Survey  correlation. 

"The  chief  characteristic  of  the  No.  6  bed,  which  averages  6  feet  in  thick- 
ness, is  the  presence  of  a  blue  band  which  divides  it  into  upper  and  lower 
benches.  This  blue  band  varies  from  soft  dust  to  hard  gray  shale,  and 
occurs  about  2  feet  above  the  floor.  In  addition  to  this  blue  band  there  are 
several  shale  and  sulphur  bands  of  variable  horizontal  and  vertical  extent. 

"The  roof  over  No.  6  coal  is  variable.  Near  Danville  the  immediate  roof 
is  a  grayish  black  shale  about  G  feet  thick.  This  shale,  lying  between  the 
coal  and  the  cap-rock  of  dark-gray  nodular  limestone  makes  an  easily  sup- 
ported roof.  In  the  vicinity  of  Westville  and  Georgetown  the  immediate  roof 
is  usually  a  gray  shale,  which  shows  no  distinct  bedding,  has  little  cohesion, 
falls  in  conchoidal  masses,  and  is  extremely  difficult  to  support.  Further, 
stringers  of  coal  extend  from  the  bed  proper  into  the  roof  material,  and 
render  the  roof  more  difficult  of  support.  In  isolated  cases  there  are  3  to  4 
inches  of  black  shale  between  the  coal  and  the  gray  shale  which  forms  the 
cap-rock.  Whenever  this  black  shale  is  broken,  air  and  moisture  disintegrate 
the  gray  shale  cap-rock,  and  the  roof  becomes  insupportable. 

"In  all  parts  of  the  Danville  district  the  floor  is  a  soft  fire  clay. 

"The  No.  7  bed  varies  in  thickness  from  2y2  to  5%  feet,  and  averages  5 
feet.  The  coal  has  two  benches  separated  by  a  clay  band  1  inch  thick,  which 
persists  through  the  bed  from  6  to  8  inches  above  the  floor.  The  two  benches 
present  no  great  difference  in  appearance  or  in  physical  character,  except 
locally,  where  the  top  bench  is  harder  and  has  a  brighter  luster.  The  No.  7 
bed  generally  has  slightly  more  impurities  than  the  No.  6  bed,  higher  volatile 
matter,  lower  fixed  carbon,  and  higher  sulphur  content  as  shown  by  analyses 
of  31  face  samples  in  No.  6  and  of  18  face  samples  in  No.  7.  The  bands  of 
pyrites  occur  persistently  at  a  height  of  20  to  26  inches  above  the  floor,  and 
sulphur  balls  or  nodular  concretions  of  pyrite  are  present  in  such  quantity 
as  to  make  profitable  their  separation  from  the  coal  by  hand  picking  in  the 
mine,  and  by  a  further  separation  on  the  surface  in  rotating  cylinders. 

"In  both  beds  in  the  district  there  are  numerous  rolls,  called  'faults,' 
or  'horsebacks'  by  the  miners.  These  rolls  appear  to  have  been  due  to  un- 
equal settling  of  the  coaly  matter  and  the  necessary  readjustment  of  the  roof 
materials,  during  the  formation  of  the  coal.  In  many  cases  the  roll  entirely 
displaces  the  coal. 

"The  mines  in  District  VIII  are  shallow,  and  the  deepest  mine  does  not 
exceed  300  feet." 


5  Andros,    S.    O.,   Coal   mining   practice   in   District  VIII    (Danville);   111,   Coal 
Mining   Investigations    Pull.    2,    1914, 


ILLINOIS    COAL   LOSSES 


33 


Method  of  Mining 

Room-and-pillar  methods  of  mining  are  employed,  with  some  ef- 
forts to  divide  the  workings  into  panels.  One  of  the  largest  com- 
panies uses  24- foot  rooms  driven  on  30- foot  centers.  Some  room 
pillars  are  drawn,  but  over  the  entire  field  the  amount  of  coal  thus  re- 
covered amounts  to  very  little.  Some  of  the  companies  try  to 
protect  the  surface  where  it  is  agricultural  land,  but  others  do  not, 


rctnn 


I  Coal  that  will  be  extracted 
m  part  or  in  whole 


ICo.il  Loj 


Fig.  7.  Section  of  mine  workings  in  Vermilion 
County  showing  coal  lost  because  of  irregular 
spacing  and  direction  of  rooms. 

as  they  do  not  have  to  pay  damages  for  surface  subsidence.  Under 
the  towns  and  railroads  the  work  is  carried  on  according  to  the  usual 
method,  except  that  more  care  is  taken  to  leave  sufficient  pillars  to 
avoid  squeezes.  In  the  north  end  of  the  district,  along  Little  Ver- 
million River,  a  great  deal  of  coal  has  to  be  left  under  branch  streams 
which  flow  into  the  river.  However,  this  coal  being  of  shallow  depth, 
it  can  be  recovered  in  a  large  part  by  stripping  operations. 


u 


ILLINOIS    COAL    LOSSES 


Losses  of  Coal 

One  company  producing  about  1,400,000  tons  per  year  reported 
that  its  extraction  is  from  55  per  cent  at  the  smaller  mines  to  65  per 
cent  at  the  larger  mines,  and  that  15  per  cent  of  the  total  loss  is  due 
to  rolls  and  faulty  conditions.  Another  company  figures  on  an  ex- 
traction of  53.43  per  cent.  Under  ordinary  conditions,  with  24-foot 
rooms  and  6-foot  pillars,  the  loss  in  pillar  coal  would  be  32  to  35  per 
cent,  and  judging  from  experience  in  the  Panhandle  and  Belmont  fields 
of  West  Virginia  and  Ohio,  the  writer  does  not  believe  that  the  mines 
in  the  Danville  field  can  get  65  per  cent  of  their  coal  when  their  faulty 
conditions  are  considered.  Without  further  information  the  writer 
can  not  see  how  the  extraction  in  this  field  can  be  over  about  57  per 
cent  in  the  underground  mines,  divided  as  shown  in  Table  9. 

Table  9. — Summa?-y  of  coal  losses  in  the  Danville  district 


Reason  for  loss 

Percentage  of  market- 
able coal  lost  in 
area  worked 

Total 
loss 

Avoidable 
loss 

Coal  left  on  roof  and  bottom 

None 
32 

Included 
in  above 

4 

7 

Coal  lost  in  room,  entry,  and  panel  pillars   (fig.  7) 
Coal  lost  in  oil  or  gas-well  pillars 

23 

Coal  lost  under  buildings,  railroads,  and  boundaries 

Coal  lost  in  handling  and  preparation,  underground 
and   surface    

Coal    lost    due    to    rolls,    thin    or    dirty    areas,    and 
streams    .       

' 

Total  loss,  per  cent 

43 

23 

AVOIDABLE  LOSS 


Owing  to  the  fact  that  some  of  the  companies  have  the  surface 
rights,  and  also  that  the  county  has  fewer  towns  and  is  more  rolling 
in  contour,  they  should  get  a  higher  extraction  than  is  possible  in  the 
Springfield  district.  The  question  of  possible  recovery  and  the  means 
of  arriving  at  it  have  been  discussed  in  the  Springfield  report,  and  based 
on  the  same  reasoning  possible  recovery  in  the  Danville  district  should 
be  80  per  cent. 


35 


PUBLICATIONS 

ILLINOIS  MINING  INVESTIGATIONS 


ILLINOIS    STATE    GEOLOGICAL    SURVEY    DIVISION 
URBANA,   ILLINOIS 


Bulletin 
Bulletin 
Bulletin 
Bulletin 
Bulletin 

1. 

3. 
10. 
11. 
14. 

Bulletin 
Bulletin 
Bulletin 

15. 
16. 

17. 

Bulletin 

18. 

Bulletin 

20. 

Bulletin 

21. 

Bulletin 

2° 

Bulletin 

23. 

Bulletin 

24. 

Bulletin 

2  5. 

Bulletin 
Bulletin 
Bulletin 

26. 
2L 
28. 

Bulletin 
Bulletin 

2  9. 
30. 

Preliminary  report  on  organization  and  method  of  investigation,  1913. 

Chemical  study  of  Illinois  coals,  bv  S.  W.   Parr,   191  6. 

Coal  Resources   of   District    1    (Longwall).   by    G.    H.    Cady,    1915. 

Coal  resources   of  District  VII,   by   Fred   H.   Kav,    1915. 

Coal    Resources    of    District    VIII    (Danville),    bv    Fred    H.    Kav    and 

K.  D.  White,   1915. 
Coal  resources  of   District  VI,   by   G.   H.    Cady,    1916. 
Coal  resources  of  District  II    (Jackson  Co.),  bv   G.   H.   Cady.    1917. 
Surface   subsidence   in   Illinois   resulting  from  coal   mining,   by   Lewis 

E.   Young,    1916. 
Tests   on    clav    materials    available    in    Illinois    coal    mines,    bv    It.    T. 

Stull   and   R.   K.   Hursh,    1917. 
Carbonization    of    Illinois    coals    in    inclined    gas    retorts,    bv    F.    K. 

Ovitz,    1918. 
The  manufacture  of  retort  coal-gas  in  the  central  states,   using   low- 
sulphur    coal    from    Illinois,    Indiana,    and    western    Kentucky,    by 

W.  A.   Dunkley  and  W.  W.   Odell.   1918. 
Water-gas    manufacture    with    central    district    bituminous    coals    as 

generator  fuel,   by  W.   W.   Odell   and  W.   A.    Dunkley.    1918. 
Mines   producing    low-sulphur   coal   in    the   central    district,    by    G.    H. 

Cady,    1919. 
Water-gas   operating  methods  with   central  district  bituminous   coals 

as   generator  fuel.      A   summary    of   experiments   on   a   commercial 

scale,    bv    W.    A.    Dunkley    and    W.    W.    Odell.    1919. 
Gas  purification   in   the   medium-size   gas   plants  of   Illinois,   by   AY.   A. 

Dunkley   and   C.    E.    Barnes,    1920. 
Coal    resources   of    District    IV,    by    G.    H.    Cady,    1921. 
Analyses  of   Illinois   coal,   compiled    by    G.    W.    Hawley.    1923. 
Preliminary    report    on     coal     stripping    possibilities     in     Illinois,     by 

Harold   E.    Culver,    19  25. 
Coal   resources  of   District    III.   by    Harold    E.   Culver,    1925. 
Coal   losses   in    Illinois,   by    C.    A.    Allen,    1925. 


Bulletin 

2. 

Bulletin 

4. 

Bulletin 

5. 

Bulletin 

6. 

Bulletin 

7 

Bulletin 

s'. 

Bulletin 

9. 

Bulletin 

12. 

Bulletin 

13. 

Bulletin 

91. 

Bulletin 

100. 

Bulletin 

113. 

Bulletin 

119. 

Bulletin 

125. 

Bulletin 

132. 

Bulletin 

144. 

Bulletin  72. 

Bulletin  83. 

Bulletin  99. 

Bulletin  102. 


EN<  1 1  X  EER  [NG    EX  PER]  M  ENT  STATION 
URBANA,     ILLINOIS 

Coal    mining    practice    in    District    VIM     (Danville),    by    S.    ( ).    Andros, 

1913. 
Coal    mining    practice    in    District    VII,    by    S.    O.    Andros,     1911. 
Coal  mining  practice  in   District  I    (Longwall),  by    S.  O.  Andros,  1 91 4. 
Coal    mining    practice    in    District   V,    by    S.    ().    Andros,    1911. 
Coal    mining    practice    in    District    11,    by    S.    ().    Andros.    1914. 
Coal  mining  practice  in    District  VI.  by  S.  O.   Andros,    1914. 
Coal    mining    practice    in    District    III,    by    S.    ().    Andros.    1915. 
Coal   mining  practice   in    District   IV.  by   S.  O".    Andros,    1915. 
Coal    mining   in    Illinois  by   S.   ().   Andros.    1915.       (Complete   resume   ,,f 

all    the    district    reports. ) 
Subsidence   resulting  from   mining,   by    L.   E.    Young  and    II.    II.   Stock, 

1916. 
Percentage  of  extraction   of  bituminous  coal   with   special   reference 

to    Illinois'    conditions,    by    C.    M.    Young-,    1917. 
Panel   system   of  coal    mining:,   by    C.    M.    Young;,    1919. 
Some   conditions    affecting;    the    usefulness    of    iron    oxide    for    city    gas 

purification,    by     W.     A.     Dunk  lev,     1921. 
The   distribution    of  the   forms   of   sulphur   in    the   coal    bed,   by    II.    F. 

Yancey   and   Thomas    Fraser,    1921. 
A    study    of    coal    mine    haulage    in     Illinois,    by     II.     II.    Stock,    .1.     It. 

Fleming;   and    A.    .1.    Hoskin,     1922. 
Power    studies    in    Illinois    coal    mining,    by    A.    .1.    Hoskin    and    T. 

Fraser,  1924. 


U.   S.    BUREAU    OF   MINES 
WASHINGTON,     D.     C. 

Occurrence    of   explosive    gases    in    coal    mines,    bv    X.    H.    Darton, 

1915. 
The    humidity    of   mine    air,    by    R.    Y.    Williams,    1914. 
Mine   ventilation   stoppings,   by    R.    V.    Williams,    1915. 
The    Inflammability    of    Illinois   'coal    dusts,    bv    J.    K.    Clement    ami    L. 

A.    Scholl,    Jr.,    1916. 


;*g 


Bulletin   138. 
Bulletin   203. 


Bulletin    234. 


Bulletin   137.      Use    of    permissible    explosives    in    the    coal    mines    of    Illinois,    bv    J. 

R.    Fleming   and    J.    W.    Koster,    1917. 
Coking-   of    Illinois    coals,    by    F.    K.    Ovitz,    1917. 
Central    district    bituminous    coals    as    water-gas    generator    fuel, 

by   W.   W.   Odell   and  W.   A.   Dunkley,    19  24. 
The  screen  sizing  of  coal,  ores  and  other  minerals,  by  E.  A.  Holbrook 

and  Thomas  Fraser,   192  4. 
Technical   Paper   190.      Methane  accumulations  from  interrupted  ventilation,  with 

special  reference  to    coal   mines    in   Illinois   and   Indiana,    bv    H.    I. 

Smith   and   Robert  J.   Hamon,    1918. 
Technical  Paper  246.     Water-gas  apparatus  and  the  use  of  central  district  coal  as 

generator    fuel,    by    William    W.    Odell,    1921. 
Technical   Paper  268.     Preparation  and  uses  of  tar  and  its  simple  crude  derivatives, 

by    W.    W.    Odell,    1922. 
Technical  Paper  2S4.     Coal    and    coke    mixtures    as    water-gas    generator    fuel,    by 

W.    W.    Odell,    1921. 
Technical   Paper  304.     Water-gas    tar    emulsions,     by     W.    W.     Odell,     1923. 
Technical   Paper  330.      Small  hose  streams   for  fighting  mine  fires,   by  L.   D.   Tracy 

and  R.  W.  Hendricks,   1924. 
Technical  Paper  361.      Cleaning    tests    of    central    Illinois    coal,    by    Thomas    Fraser 

and  H.  F.  Yancey.  1925. 


